Myocardial glucose and fatty acid metabolism is altered and associated with lower cardiac function in young adults with Barth syndrome

Background: Barth syndrome (BTHS) is a rare X-linked condition resulting in cardiomyopathy, however; the effects of BTHS on myocardial substrate metabolism and its relationships with cardiac high-energy phosphate metabolism and left ventricular (LV) function are unknown. We sought to characterize myocardial glucose, fatty acid (FA), and leucine metabolism in BTHS and unaffected controls and examine their relationships with cardiac high-energy phosphate metabolism and LV function. Methods/Results: Young adults with BTHS (n = 14) and unaffected controls (n = 11, Control, total n = 25) underwent bolus injections of ¹⁵O-water and 1-¹¹C-glucose, palmitate, and leucine and concurrent positron emission tomography imaging. LV function and cardiac high-energy phosphate metabolism were examined via echocardiography and ³¹P magnetic resonance spectroscopy, respectively. Myocardial glucose extraction fraction (21 ± 14% vs 10 ± 8%, P =.03) and glucose utilization (828.0 ± 470.0 vs 393.2 ± 361.0 μmol·g⁻¹·min⁻¹, P =.02) were significantly higher in BTHS vs Control. Myocardial FA extraction fraction (31 ± 7% vs 41 ± 6%, P <.002) and uptake (0.25 ± 0.04 vs 0.29 ± 0.03 mL·g⁻¹·min⁻¹, P <.002) were significantly lower in BTHS vs Control. Altered myocardial metabolism was associated with lower cardiac function in BTHS. Conclusions: Myocardial substrate metabolism is altered and may contribute to LV dysfunction in BTHS. Clinical Trials #: NCT01625663.